This invention relates to a fault detection device for occupant protective systems for use in automotive vehicles, and more particularly to such a device which detects faults in squibs used in the occupant protective systems.
Occupant protective systems, such as an inflatable air bag system using gas-inflatable air bags, and a pre-tensioning system which tensions a seat belt when an accident occurs, have conventionally been used to protect occupants in automotive vehicles in the event that the vehicle is involved in a crash, for instance.
In order to detect faults in squibs for actuating respective air bags or pre-tensioners, a fault detection device has been proposed e.g. by Japanese Provisional Patent Publication (Kokai) No. 60-206753, which includes a plurality of fault detection circuits to detect faults in respective squibs.
An occupant protective system of this kind usually employs a plurality of air bags or pre-tensioners which are arranged at a driver's seat and an assistant driver's seat of a vehicle, for instance.
However, having a plurality of fault detection circuits which detect faults in the respective squibs separately from each other, the proposed fault detection device requires an increased number of component parts, resulting in an increased manufacturing cost as well as difficult maintenance and inspection of the device.